某大负荷涡轮过渡段设计探索

Design exploration of a highly loading intermediate transition duct of turbine

对某大负荷过渡段进行了探索设计和数值模拟。对比分析表明:在支板数很少的情况下,支板厚度分布对主流区的流动影响很小,主要通过叶型曲率分布来影响支板表面逆压梯度和分离。凹曲率和凸曲率搭配可以有效控制轮毂、机匣和支板叶尖的流动分离。可以通过支板周向倾斜改变支板叶型在S1流面的安装角,从而起到改变攻角效应和控制流动分离的作用。在条件允许的情况下应尽可能将支板部分或全部置于主流逆压梯度较小的区域以减小支板表面压力梯度和分离风险。

Aerodynamic design and numerical simulation were carried out to investigate a intermediate transition duct （ITD）. Results of the analyses and comparisons showed that the thickness distribution of ITD strut vane （SV） had little impact on the main flow when SV number was small, while the pressure gradient and separation of SV surface were affected mainly through the profile curvature distribution. The flow separation in the region of hub, shroud and SV＇s tip was controlled effectively with the combination of concave and convex curvature. The stagger angles of the SV on S1 stream surface were changed by circumferential lean to impact the effect of attack angle and depress the flow separation. The SV should be placed in the main flow with low pressure gradient as more as possible no matter part or all to decrease the pressure gradient and risk of flow separation.